4Y7K

Structure of an archaeal mechanosensitive channel in closed state


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.5 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.259 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Mechanical coupling of the multiple structural elements of the large-conductance mechanosensitive channel during expansion

Li, J.Guo, J.Ou, X.Zhang, M.Li, Y.Liu, Z.

(2015) Proc.Natl.Acad.Sci.USA 112: 10726-10731

  • DOI: 10.1073/pnas.1503202112
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The prokaryotic mechanosensitive channel of large conductance (MscL) is a pressure-relief valve protecting the cell from lysing during acute osmotic downshock. When the membrane is stretched, MscL responds to the increase of membrane tension and open ...

    The prokaryotic mechanosensitive channel of large conductance (MscL) is a pressure-relief valve protecting the cell from lysing during acute osmotic downshock. When the membrane is stretched, MscL responds to the increase of membrane tension and opens a nonselective pore to about 30 Å wide, exhibiting a large unitary conductance of ∼ 3 nS. A fundamental step toward understanding the gating mechanism of MscL is to decipher the molecular details of the conformational changes accompanying channel opening. By applying fusion-protein strategy and controlling detergent composition, we have solved the structures of an archaeal MscL homolog from Methanosarcina acetivorans trapped in the closed and expanded intermediate states. The comparative analysis of these two new structures reveals significant conformational rearrangements in the different domains of MscL. The large changes observed in the tilt angles of the two transmembrane helices (TM1 and TM2) fit well with the helix-pivoting model derived from the earlier geometric analyses based on the previous structures. Meanwhile, the periplasmic loop region transforms from a folded structure, containing an ω-shaped loop and a short β-hairpin, to an extended and partly disordered conformation during channel expansion. Moreover, a significant rotating and sliding of the N-terminal helix (N-helix) is coupled to the tilting movements of TM1 and TM2. The dynamic relationships between the N-helix and TM1/TM2 suggest that the N-helix serves as a membrane-anchored stopper that limits the tilts of TM1 and TM2 in the gating process. These results provide direct mechanistic insights into the highly coordinated movement of the different domains of the MscL channel when it expands.


    Organizational Affiliation

    National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Large conductance mechanosensitive channel protein,Riboflavin synthase
A, B, C, D, E
275Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440)Methanosarcina acetivorans (strain ATCC 35395 / DSM 2834 / JCM 12185 / C2A)
This entity is chimeric
Mutation(s): 0 
Gene Names: ribC,
EC: 2.5.1.9
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Mechanosensitive
Protein: 
MscL mechanosensitive channel in closed state
Find proteins for Q58584 (Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440))
Go to UniProtKB:  Q58584
Find proteins for Q8TNK0 (Methanosarcina acetivorans (strain ATCC 35395 / DSM 2834 / JCM 12185 / C2A))
Go to UniProtKB:  Q8TNK0
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.5 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.259 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 87.292α = 90.00
b = 140.368β = 90.00
c = 182.544γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
PHASERphasing
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data

  • Deposited Date: 2015-02-15 
  • Released Date: 2015-08-26 
  • Deposition Author(s): Li, J., Liu, Z.

Funding OrganizationLocationGrant Number
Chinese Academy of SciencesChinaXDB08020302
Ministry of Science and TechnologyChina2014CB910301

Revision History 

  • Version 1.0: 2015-08-26
    Type: Initial release
  • Version 1.1: 2015-09-09
    Type: Database references